Power lawn mowers are widely used to maintain and enhance the appearance of turf grass and other vegetation. In one simple arrangement, a generally rectangular blade is rotated in a horizontal plane at the desired cutting height. The blade sweeps out a circle, and sharpened cutting zones on the leading edges of the blade cut the grass at the desired height as the entire mower travels across the lawn. The blade may also include raised “wings” on its trailing edges, to lift the grass as it is cut by the sharpened edges. In a single-blade mower, the blade may typically be about three inches across and 18-24 inches long, so that the mower cuts a swath about 18-24 inches wide. The blade may be turned by a motor such as a gasoline or electric motor, and in some mowers, power from the motor is also be used to propel the mower itself. Often, the blade is attached directly to the vertical shaft of the motor.
While such a narrow swath may be satisfactory for cutting small areas, it is often desirable for a mower to cut a wider swath, to reduce the time required to mow a larger area. Because various difficulties arise when a mower blade exceeds about 24 inches, multi-blade mowers have been developed. In a typical multi-blade mower, multiple blades rotate on spaced-apart spindles, each spindle having a single blade mounted thereon, and are transported in parallel across the lawn. The blades of conventional multi-blade mowers are oriented in the same plane and are commonly offset or timed to provide horizontal overlap between the blade swaths. The blades cut an overall swath that approaches the sum of the lengths of the blades, less the overlap necessary to ensure that no gaps exist in the cut swath. That is, a two-blade mower may cut a swath just under twice the width of a mower having a single blade of the same length as each of the two blades. A multiple-blade mower thus achieves improved cutting productivity, while avoiding the difficulties of longer blades. The blades are typically housed within a single deck that has internal baffling that works to minimize conflicting airflow between adjacent blades and also to direct and expedite the discharge of cut clippings from within the deck.
There is a need for improved multi-blade mowers.